Replacement of endoprosthetic implants within a two years follow-up period: a statutory health insurance routine data analysis.

BACKGROUND: The statutory health insurance system embodies a large amount of data on the treatments of their members. Depending on joint, prosthesis type, patient activity and comorbidity, knee and hip replacements can last up to 20 years. Based on statutory health insurance data the main object of this analysis was to investigate how high the early revision rate of replacements actually is. METHODS: The number of replacements in the years 2005 and 2006 has been extracted from the TK database for hip (OPS-Code 5-820, n = 20,875), knee (OPS 5-822, n = 13,466), upper limbs (OPS 5-824, n = 901), and lower limbs (OPS 5-826) replacements. This data has then been related to each consecutive operation (i. e. change or excision of joint endoprosthesis) over a joint-specific observation period of two years. RESULTS: In 3.7% of the cases joint replacements stood for less than 2 years (hip 3.5%, knee 3.8%, upper limbs 6.5%, and lower limbs 5.5%). There is a significantly positive correlation between the treatment data of the hospitals and the outcome as to low rates of reoperations at early stages. The main reason for short lifetime (76 - 81%) is mechanical failure. CONCLUSION: The percentage of joint endoprostheses with significantly short lifetimes has been unexpectedly high. The de facto lifetimes of joint endoprostheses thus often do not match the manufacturers' information. The authors strongly support the idea of a national endoprosthesis register as such a register could give detailed information on firstly whether these deficits are due to material defects, osteolysis or dislocation and secondly which products are mainly affected.

Computer-assisted navigation increases precision of component placement in total knee arthroplasty.

UNLABELLED: In our clinical study, 200 total knee arthroplasties were evaluated to compare the use of the OrthoPilot system with conventional mechanical instrumentation. Long-term outcome of total knee replacement depends mainly on the accuracy of implant positioning and restoration of the mechanical leg axis. Our experience was that navigation could achieve a greater degree of accuracy concerning the aforementioned aspects. Among 513 primary-inserted total knee replacements, 100 navigated knees were compared with 100 conventionally implanted knees after matching the two groups of patients by gender, body mass index, age, preoperative deformities, radiographic findings, and operating time. Three weeks after surgery, the radiographic results were significantly better in the computer-assisted group compared with the results in the conventional group when we assessed component positioning in four axes. Only the sagittal tibial component angle was not significantly different. Total knee arthroplasty using the OrthoPilot system led to increased precision of tibial and femoral component positioning in comparison with hand-guided replacement surgery. An additional 10 minutes of operating time was acceptable. Navigation-specific complications were not seen, and the number of outliers decreased. Because computer navigation in orthopaedics is a new technology, data regarding long-term outcomes are not available. LEVEL OF EVIDENCE: Diagnostic study, Level II-1 (retrospective study). See the Guidelines for Authors for a complete description of levels of evidence.